Safety grenade

ABSTRACT

A grenade having control means for arming the grenade in response to a predetermined free flight thereof and for firing an armed grenade in response to interruption of said free flight of the grenade, said control means having a safety time factor for preventing arming of the grenade in response to short periods of free flight. Means can also be provided for preventing unintentional operation of the grenade.

United States Patent Fay [451 Jan. 25, 1972 [54] SAFETY GRENADE2,996,009 8/l96l Donahue, Jr. et al 102/76 [72] Inventor: James P. Fay,l8 France St., Norwalk, Primary Examiner koben stahl Conn 0685]Attorney-Johnson & Kline [22] Filed: Aug. 6, 1969 [57] ABSTRACT [211App]. No.: 847,852

A grenade having control means for arming the grenade in response to apredetermined free flight thereof and for firing [52] Cl "102/64, 02/76an armed grenade in response to interruption of said'free flight [51] ICl 27/08 of the grenade, said control means having a safety time factor[58] Field ofSearch ..l02/64, 76 for Preveming arming f the grenade inresponse to she" periods of free flight. Means can also be provided forprevent- [561 Retewnces ing unintentional operation of the grenade.

UNITED STATES PATENTS 1 1 Claims, 1 1 Drawing Figures l,2l6,078 2/1917Coleman ..l02/76 m II M I56 5&3 49 N PATENTED JANZS 1912 SHEET 1 BF 2 INVENTOR. James P F Q BY i 197 TOR/V576 PATENTED JANZS r972 SHEET 2 OF 2INVENTOR f ay 147' 7' ORA/E Y5 Jay/65 SAFETY GRENADE I-Ieretofore,grenades were usually activated by a fuse which was normally ignited bya spring-operated striker and the fuse calibrated to set off the maincharge at a predetermined interval of time thereafter. This has severaldisadvantages. Accidents can occur if a man should drop a grenade so asto accidentally ignite the fuse. Also, there is a danger that if throwntoo soon, it can be picked up and thrown back before the fuse sets offthe charge. To avoid this, it has been the practice of arming thegrenade and holding it for a few seconds so that it will explode beforeit can be picked up and returned.

The present invention provides a grenade having a novel control forpreventing the difficulties heretofore encountered. In carrying out theinvention, the grenade is provided with a means for arming the grenadein response to predetermined free flight of the grenade and for firingthe armed grenade in response to interruption of said free flight of thegrenade.

A feature of the invention resides in the safety construction whereinthe grenade is armed only after a predetermined in terval of free flightand should the free flight cease prior to the arming, the controlreturns to normal position. Thus, if the grenade is dropped and/oraccidentally placed in free flight for a short period of time, it willnot become armed.

Another feature of the invention resides in the fact that the controlmeans can be rendered inoperative to arm the grenade until a pin orother safety unit has been intentionally removed, thus preventingaccidental arming of the grenade during storage or handling.

The control member can be a mechanical control member or an electricalcontrol member and is highly effective in preventing accidentaldischarge of the grenade.

Other features and advantages of the invention will be apparent form thespecification and claims when considered in connection with theaccompanying drawings wherein:

FIG. 1 is a sectional view of one form of the invention.

FIG. 2 is a partial view of FIG. 1 with the grenade in armed position.

FIG. 3 is a view similar to FIG. 2 with the grenade in firing position.

FIG. 4 is a fragmentary view showing the dashpot.

FIG. 5 is a view of a safety device for the grenade.

FIG. 6 is a sectional view of another form of the invention.

FIG. 7 is a view of the sear means of FIG. 6.

FIG. 8 is a sectional view of still another form of the invention.

FIG. 9 is a detail of the control member of FIG. 8.

FIG. 10 is a sectional view of a further form of the invention.

FIG. 11 is a view taken along line l1ll of FIG. 10.

FIG. 12 is a sectional view showing a diagrammatic electrical circuit ofa still further form of the invention.

As shown in FIG. 1, the grenade has a frangible body 10, preferablymetal, filled with a charge of explosive material 11, preferably apowder. A firing and control device comprises a plug 12 threaded into anopening 13 in the body 10 and has a tubular housing 14 threaded on theplug. The housing has a closed end 15 carrying a primer or detonator 16which is located within the charge of explosive material to fire thecharge when actuated. A firing element 17 having a firing pin 17a foractuating the primer is slidably mounted in the housing and is normallyurged to firing position by a spring 18 having one end engaging the plug12 and the other end bearing on a flange 19 on the firing pin. Thefiring pin is held in retracted position against the urging of spring 18by a sear member or latch 20 having one end pivoted at 21 on the plugand having a latch element 22 at the other end extending under ashoulder 23 on the firing pin when the latter is in retracted position.When the sear is released by moving the latch element 22 from theshoulder 23, the spring moves the firing element 17 downwardly. The pin17a, upon impact with the primer 16, will fire the charge and explodethe grenade.

The novel control for the sear means operates to arm the grenade inresponses to a predetermined free flight and to fire the armed grenadein response to interruption of said free flight thereof.

In the control shown in FIGS. 1-5, a control strand or cord 30 has aweight 31 herein illustrated as a ball secured at one end and disposedin a cavity 32, preferably spherical, formed in a projecting headportion 33 of the plug 12. A tubular pedestal 34 is carried by the plugand projects into the cavity as shown in FIG. 1. The strand passesthrough the pedestal and is connected to a piston 35 operating incylinder 36 formed on the plug to form a control dashpot.

The strand is then connected to a sear control or blocking member 37disposed in a bore 38 in the firing member. It is normally positioned.as shown in FIG. I. In this position it engages the sear 20 and blocksthe sear against release of the latch 22 from the shoulder 23 of thefiring member. The end of the strand is connected to a light spring 39which tends to draw the strand downwardly when the device is in freeflight so that the ball moves from contact with the wall as shown inFIG. 1 until the ball 31 is seated on the pedestal as shown in FIG. 2.

As the strand moves downwardly under the action of spring 39, it iscontrolled by the dashpot to provide a timing operation. The strandmoves the blocking member 37 past a resilient actuator 40 for the searto the position shown in FIG. 2 to arm the device.

The dashpot as illustrated in FIG. 4 has a flap valve 41 under thepiston normally closing a plurality of ports 42 in the piston to sealthe ports resulting in the slow downward movement of the piston.However, when the free flight of the grenade is interrupted, the ball 31falls off of the pedestal 34 and draws the strand 30 upwardly againstspring 39. The strand can move relatively quickly in this directionsince the flap valve 41 opens the vent ports 42.

As the strand moves upwardly, the control or blocking member 37 movesupwardly and engages the sear actuator 40 to pivot the sear and retractthe latching element 22 from the shoulder 23. The spring 18 immediatelydrives the firing element 17 downwardly to cause the firing pin 17a tostrike the primer 16 and discharge the explosive material.

An advantage of this control resides in the fact that should the grenadebe subjected to free flight for a period of time less than that requiredby the dashpot for arming the grenade, as might be occasioned byhandling the grenade or by dropping it to the ground, the ball, uponinterruption of said free flight of the grenade, automatically quicklydraws the strand upwardly and resets the control means. This provides animportant safety factor.

The form of the invention shown in FIGS. 6 and 7 is similar in structureand operation as that of FIG. 1 with the exception of the structure andoperation of the sear means. As shown, the sear means comprises anelongate element 120 having one end pivoted on the closed end of thehousing 14 at 121. The sear extends upwardly through an aperture in theend of the firing element 117. It has a latch element 122 normallyengaging the end of the firing element at 123 and holding the firingelement in retracted position against the action of spring 18. The upperend is curved at 111 and has a narrow slot 112 communicating with alarge opening 113 (FIG. 7). The upper end extends into the enlarged bore138 as shown in FIG. 6 and has an anchor 114 for the spring 39.

In operation the control or blocking member 37 is in normally blockingposition as shown in FIG. 6. When the grenade is in free flight, theball 31 is moved to the top of the pedestal by spring 39. The strand 30moves the blocking member 37 downwardly and it passes through theenlarged opening 113 with the strand passing through slot 112 and thusarming the grenade. Upon interruption of free flight of the armedgrenade, the ball 31 leaves the pedestal drawing the strand 30 upwardly.This will move the upper end of the sear means to the right in FIG. 6and release the latch element 122 from contact with the wall at 123 andpermit the spring 13 to move the firing element 117 downwardly and causethe firing pin 1 17a to strike the primer 16 and fire the grenade.

In the form of the invention shown in FIGS. 8 and 9, control is similarto that in FIG. I, with the exception of the sears and sear-actuatingmeans which is as shown in FIG. 9. It comprises block 210 secured to thestrand 3% and carrying a pair of spring legs 211, M2 urged to theposition of H6. 8. The sears 22% are pivotally carried by the plug 12and have latches 222 extending under the shoulders 223 on the firingpin, as shown in FIG. 8. In arming the device, when it is in freeflight, the spring 39 moves the strand downwardly, removing the blockingelement 37 from behind the sears. As the strand moves down, the legs211, 212 move inwardly to pass the ends of the sears and then outwardlyto extend under the shoulders 220a on the scars. As the free flight isinterrupted, the ball falls off the pedestal drawing the strandupwardly. The legs 211, 212 spread outwardly. This outward movementcauses the sears to pivot with their upper ends moving outwardly andremoving the latches 222 from shoulders 223 on the firing pin, whereuponspring 13 urges the firing pin to firing position.

In the form of the invention shown in FIGS. and M, the control means issimilar to that shown in H6. ll, except that the sears 320 forcontrolling the firing are arcuate elements 322 cooperating with aV-groove 323 on the end of the firing member 317. The sears are held inplace by the ends of resilient arms 3MB extending from a sleeve 311islidable in bore 338 in the housing part 31% secured to the plug 12. Thesleeve 311 has resilient latch fingers 315 engaging shoulders 316 in thehousing part 314a which will prevent the sleeve from sliding upward. Thelatch fingers 315 have hooked members 330 extending upwardly tocooperate with a firing ring 331 carried by the dashpot piston 335. Thering has a cam surface 332 cooperating with the hooked members 330 toretract the latches on the sleeve during the downward movement of thering with the strand 30 under the urge of spring 39 during free flightof the grenade to free the sleeve. The ring has a free edge 333 toengage the hooks 330 on the sleeve to withdraw the sleeve in an upwarddirection by the upward movement of the strand 30 upon interruption ofthe free flight. This causes the resilient arms 31% to be moved frombehind the sears. The sears 320 move out of the groove 323 in the firingmember 317. This enables the spring 318 to move the firing member 317into firing position.

If desired, means can be provided to prevent unintentional firing of thedevice. While this may take many forms, it is herein illustrated as ameans applicable to the forms of the invention shown in FIGS. ll, 6, 8and ll) for preventing movement of the strand 30 until a safety deviceis removed. As shown in FIG. 5, the head portion 33 of the plug 112opposite the pedestal 34 has an aperture 45 to receive a hollow pin 46slidable in the aperture and having an O-ring 17 sealing the aperture.The hollow pin is adapted to slide over the pedestal, as shown in MG. 5,to grip the strand and hold it against accidental movement. Theprojecting portion of the pin has a ring 48 which may be gripped towithdraw the pin. It is only after the pin is withdrawn that the strandcan move to arm the grenade in response to free flight and fire thegrenade in response to interruption of said free flight.

The foregoing forms of the invention have mechanically controlled armingand firing means. in the form of the invention shown in FIG. 12 anelectrical control means is provided. As shown, the spherical cavity 32in the head portion 33 of the plug 12 threaded in the body it) isprovided with an insulating liner 5% and supports two spaced electricalcontacts 5E0, 502. Contact 501 is connected through a normally closedswitch 503 to the terminal of a battery 5&4 with the other terminal ofthe battery being grounded.

A safety pin 503a normally maintains the switch in open position untilit is desired to fire the grenade at which time the pin 50311 iswithdrawn to permit the normally closed switch to complete the circuittherethrough.

The contact 502 is connected through a lead 505 to a resistor 506 and acapacitor 507 to ground. Also the lead connects through a resistor 593to a unijunction transistor 5439 and to a firing member or squib 516 toground. The squib 516 is usually located in the housing M in inner wallE5 in place of the primer l6, and battery, resistors, capacitor andtransistor are usually potted into a single unit (not shown) disposedwithin the housing M.

The liner 500 has a quantity of electrolyte E stored therein andnormally out of engagement with the contacts 501. 502 as shown in W6.12. However, when the grenade is in free flight the electrolyte willmove to the dot-and-dash position and will close the circuit betweencontacts 501, 502.

With the circuit closed the current will flow through the resistor 506and charge the capacitor 597 at a predetermined rate and providing thedesired time delay for arming the grenade. The current will also flowthrough resistor 508 to provide a small bias on the transistor 509. Whenthe free flight of the grenade is interrupted, after the grenade hasbeen armed, the electrolyte B will return to normal position and openthe circuit. This causes the bias current to become zero whereupon thecapacitor discharges through its connection to the transistor 509 toground and ignites the squib and fires the charge in the grenade.

Variations and modifications may be made within the scope of theinvention and portions of the improvements may be used without others.

l claim:

l. A grenade having an explosive charge, means including sear means forfiring said charge, and control means for controlling the firing of saidcharge, including a strand having means thereon for normally maintainingsaid strand in a retracted position, a blocking means carried by saidstrand for engaging and preventing actuation of said sear means to firesaid charge with said strand in normal position, means for moving saidstrand from normal position in response to free flight of the grenadefor a predetermined time, movement of said strand from said normalposition moving the blocking means from said blocking position to anarmed position with respect to said sear means, interruption of saidfree flight causing said strand to be retracted to normal position andcausing the armed sear means to be actuated to fire the explosivecharge.

2. The invention as defined in claim ll wherein there is a safety meansengaging said strand and preventing operation of the control means untilthe safety means is positively removed.

3. The invention as defined in claim 1 wherein the control meansincludes time delay action means connected to said strand to preventarming the device by accidental free flight thereof for a period of timeless than the time consumed by the delay action means.

4. The invention as defined in claim 3 wherein the time delay actionmeans comprises a dashpot for slowing the action of the control meansfrom normal condition to am the device, said dashpot having vent meansto permit the control means to retum to a normal condition in the eventthe free flight ceases before the time delay means has completed itsfunction.

5. A grenade device comprising a frangible body, a charge of explosivematerial within the body, means for firing the charge, and control meansfor the firing means comprising an actuating element normally held inretracted position, a blocking means normally positioned in blockingrelation to said firing means and connected to said actuating element,said blocking means being moved from blocking relation to an anningposition in response to predetermined movement of said actuating elementfrom normal position as a result of free flight of the device, saidactuating element actuating the armed device for firing the charge onreturn of the actuating element to said normal position in response tointerruption of said free flight of the device.

6. The invention as defined in claim 5 wherein the means for firing thecharge includes a spring-urged firing pin and a releasable sear normallyholding the firing pin in retracted position and the control meansincludes a control member for normally preventing release of said searand movable with respect to said sear to arm the device in response tofree flight of the device and for causing the sear to release the firingpin in response to the interruption of said free flight of the device.

7. The invention as defined in claim 5 wherein the control means forfiring the charge comprises a plug mounted on said body, a tubularhousing on said plug and having a closed inner end with said primermounted therein to be disposed in said charge, a firing pin movable inthe housing and urged to firing position by resilient means, sear meansholding said firing pin in retracted position, and means for actuatingthe sear means comprising a flexible strand having a weight at one enddisposed in and resting on the wall of a cavity larger than the weightand formed in said plug, said strand passing through a pedestalprojecting into said cavity and connected to a time delay means and to acontrol element for the sear and having the other end connected toresilient takeup means for the strand whereby upon free flight of thegrenade the resilient takeup means draws the flexible strand downwardlyas controlled by the time delay means and moves the weight into aposition on the pedestal, the movement of the strand enabling thecontrol element to be moved into operating relation to the sear meansand upon interruption of the free flight of the grenade the weight movesback to the original position causing retraction of the strand andmoving of the control element to release the sear means from the firingelement to enable the firing pin to be moved under the urge of resilientmeans to firing position.

8. The invention as defined in claim 5 wherein the means for firing thecharge comprises a tubular housing having a closed inner end with saidprimer mounted therein to be disposed in said charge, a firing pinslidable in the housing and urged to firing position by resilient means,sear means holding said firing pin in retracted position, and controlmeans including means for actuating the sear means comprising a flexiblestrand having a weighted ball at one end disposed in and resting on thewall of a large cavity in a spherical chamber connected to said housing,said strand passing through a pedestal projecting into said chamber andconnected to a time delay means and to a blocking element for the searand having the other end connected to resilient takeup means for thestrand whereby upon free flight of the grenade the resilient takeupmeans draws the flexible strand downwardly as controlled by the timedelay means and moves the ball into a position on the pedestal, themovement of the strand enabling the blocking element to be moved out ofblocking relation to the sear means and upon interruption of the freeflight of the grenade the weighted ball moves off of the pedestal andback into engagement with the wall causing retraction of the strandmoving of the blocking element to release the sear means to enable thefiring pin to move under the urge of resilient means to firing position.

9. The invention as defined in claim 6 wherein the releasable sear ispivoted intermediate its ends and has a shoulder adjacent the upper endfor engagement by the control means, and said control member comprises aresilient actuator movable past the shoulder for arming the device andfor engaging said shoulder to move the sears to release position duringthe firing operation.

10. The invention as defined in claim 6 wherein the sears comprisearcuate shoes normally urged by spring fingers carried by a slidablesleeve into engagement with a groove on the firing pin to hold the saidpin in retracted position, and said control member having a firing ringinterlocking with said sleeve in an arming position and moving said ringand spring fingers to release the sears from holding relation with thefiring pin to enable the pin to fire the charge.

1 l. The invention as defined in claim 5 wherein the control meanscomprises a flexible strand having a weight at one end resting on thewall of a spherical cavity, a tubular pedestal projecting into saidcavity and through which the strand passes, a control member carried bythe strand and a resilient takeup for the strand to cause the strand tomove in one direction and the ball to be seated on the pedestal and thecontrol member arm the device in response to free flight of the grenade,said ball falling from said pedestal upon interruption of said freeflight of the grenade and causing the strand to move in the oppositedirection causing the control member to actuate means for firing thearmed grenade.

STATES PATENT OFFICE UNETED PO-105O Patent No.

Inventor(s) James P. Fay

It is certified that error appears in the above-identifiedpatent andthat said Letters Patent are hereby corrected as shown below:

column 1, line 33 "form" should read from; line 73,

"responses" should read --response--;

column 3, line 60 "510" should read --5o1--;

column 6, line 5 after "strand" --and-- should be inserted.

Signed and sealed this lOth.day of October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSGHALK Attesting Officer Commissionerof Patents as PATENT OFFICE CQRRECHON STA UNETED S t t n 2 m. e 7 t d t9 a e u a l m t 2 K P do T 7 L 3 e 9 e 0 f 5 ie 3 s 1 M 2 b 7 n C u i rS r y m e 6 Te r 80 n e b Tn 2 u b m 3 5 .1 m h; u m m as o J w me 3 uR1 bd OS O f E ae rn h o B 6U. f0 1 S.. 00 d h e P m y R C .8 tr .8 a tr e d a no r d .D ic w d w m P: m M e a O Q a rd 6 1 er a T mm mm d "d mE u l n h m x; y 0d u a t a 0a hl o r F r Su h t d rt 0 s S e nb D m n.w u an Ti H F 3 m o r e m w 8 S b? O 1 6 S 9 T1 7 e t fs 5 t r 8 m m ne n f d we a a ee S a. n c i 6 J it 3n 0 a Ci 3 ft 30 6 5 Tf Fu 6 ie P dEf AM L 8S 6 e 6 L0 3 a me n n n F c 1; l 8 0g \1 a l" l l i S SS S 1 Ol 9 J t t N r m l 3 6 3 ms t w Ih Le Ae n n t n A t W t w V d m w mm a nn 1 l l P I a o o o 2 c c

1. A grenade having an explosive charge, means including sear means forfiring said charge, and control means for controlling the firing of saidcharge, including a strand having means thereon for normally maintainingsaid strand in a retracted position, a blocking means carried by saidstrand for engaging and preventing actuation of said sear means to firesaid charge with said strand in normal position, means for moving saidstrand from normal position in response to free flight of the grenadefor a predetermined time, movement of said strand from said normalposition moving the blocking means from said blocking position to anarmed position with respect to said sear means, interruption of saidfree flight causing said strand to be retracted to normal position andcausing the armed sear means to be actuated to fire the explosivecharge.
 2. The invention as defined in claim 1 wherein there is a safetymeans engaging said strand and preventing operation of the control meansuntil the safety means is positively removed.
 3. The invention asdefined in claim 1 wherein the control means includes time delay actionmeans connected to said strand to prevent arming the Device byaccidental free flight thereof for a period of time less than the timeconsumed by the delay action means.
 4. The invention as defined in claim3 wherein the time delay action means comprises a dashpot for slowingthe action of the control means from normal condition to arm the device,said dashpot having vent means to permit the control means to return toa normal condition in the event the free flight ceases before the timedelay means has completed its function.
 5. A grenade device comprising afrangible body, a charge of explosive material within the body, meansfor firing the charge, and control means for the firing means comprisingan actuating element normally held in retracted position, a blockingmeans normally positioned in blocking relation to said firing means andconnected to said actuating element, said blocking means being movedfrom blocking relation to an arming position in response topredetermined movement of said actuating element from normal position asa result of free flight of the device, said actuating element actuatingthe armed device for firing the charge on return of the actuatingelement to said normal position in response to interruption of said freeflight of the device.
 6. The invention as defined in claim 5 wherein themeans for firing the charge includes a spring-urged firing pin and areleasable sear normally holding the firing pin in retracted positionand the control means includes a control member for normally preventingrelease of said sear and movable with respect to said sear to arm thedevice in response to free flight of the device and for causing the searto release the firing pin in response to the interruption of said freeflight of the device.
 7. The invention as defined in claim 5 wherein thecontrol means for firing the charge comprises a plug mounted on saidbody, a tubular housing on said plug and having a closed inner end withsaid primer mounted therein to be disposed in said charge, a firing pinmovable in the housing and urged to firing position by resilient means,sear means holding said firing pin in retracted position, and means foractuating the sear means comprising a flexible strand having a weight atone end disposed in and resting on the wall of a cavity larger than theweight and formed in said plug, said strand passing through a pedestalprojecting into said cavity and connected to a time delay means and to acontrol element for the sear and having the other end connected toresilient takeup means for the strand whereby upon free flight of thegrenade the resilient takeup means draws the flexible strand downwardlyas controlled by the time delay means and moves the weight into aposition on the pedestal, the movement of the strand enabling thecontrol element to be moved into operating relation to the sear meansand upon interruption of the free flight of the grenade the weight movesback to the original position causing retraction of the strand andmoving of the control element to release the sear means from the firingelement to enable the firing pin to be moved under the urge of resilientmeans to firing position.
 8. The invention as defined in claim 5 whereinthe means for firing the charge comprises a tubular housing having aclosed inner end with said primer mounted therein to be disposed in saidcharge, a firing pin slidable in the housing and urged to firingposition by resilient means, sear means holding said firing pin inretracted position, and control means including means for actuating thesear means comprising a flexible strand having a weighted ball at oneend disposed in and resting on the wall of a large cavity in a sphericalchamber connected to said housing, said strand passing through apedestal projecting into said chamber and connected to a time delaymeans and to a blocking element for the sear and having the other endconnected to resilient takeup means for the strand whereby upon freeflight of the grenade the resilient takeup means draws the flexiblestrand downwardlY as controlled by the time delay means and moves theball into a position on the pedestal, the movement of the strandenabling the blocking element to be moved out of blocking relation tothe sear means and upon interruption of the free flight of the grenadethe weighted ball moves off of the pedestal and back into engagementwith the wall causing retraction of the strand moving of the blockingelement to release the sear means to enable the firing pin to move underthe urge of resilient means to firing position.
 9. The invention asdefined in claim 6 wherein the releasable sear is pivoted intermediateits ends and has a shoulder adjacent the upper end for engagement by thecontrol means, and said control member comprises a resilient actuatormovable past the shoulder for arming the device and for engaging saidshoulder to move the sears to release position during the firingoperation.
 10. The invention as defined in claim 6 wherein the searscomprise arcuate shoes normally urged by spring fingers carried by aslidable sleeve into engagement with a groove on the firing pin to holdthe said pin in retracted position, and said control member having afiring ring interlocking with said sleeve in an arming position andmoving said ring and spring fingers to release the sears from holdingrelation with the firing pin to enable the pin to fire the charge. 11.The invention as defined in claim 5 wherein the control means comprisesa flexible strand having a weight at one end resting on the wall of aspherical cavity, a tubular pedestal projecting into said cavity andthrough which the strand passes, a control member carried by the strandand a resilient takeup for the strand to cause the strand to move in onedirection and the ball to be seated on the pedestal and the controlmember arm the device in response to free flight of the grenade, saidball falling from said pedestal upon interruption of said free flight ofthe grenade and causing the strand to move in the opposite directioncausing the control member to actuate means for firing the armedgrenade.